A multi-year conference grant is being proposed to support a forum for researchers to pursue collaborative studies of the molecular genetics of obsessive compulsive disorder (OCD). This application is consistent with NIMH initiatives to facilitate meetings in which researchers come together to establish mechanisms for collaborating in a manner that would facilitate the detection of genes predisposing to psychiatric disorders. At the present time, there are approximately 50 researchers who have attended the first two meetings of this group. These individuals come from 12 [unreadable] foreign countries and from 13 different research centers in the United States. The group has already met twice and will be meeting again in April 2004. OCD is a serious psychiatric condition that can have debilitating affects on both adults and children. The importance of genetic factors in OCD has been demonstrated by twin and family aggregation studies. Furthermore, recent molecular genetic studies have begun to provide evidence that specific genes may play a role in the manifestation of the disorder. [unreadable] Although these preliminary results are encouraging, several considerations suggest that fully clarifying the genetic architecture of OCD will require large samples and collaborative efforts. It is clear from ongoing studies of the genetics of schizophrenia, autism, Gilles de la Tourette's syndrome, ADHD and bipolar disorder that are consistent with statistical considerations regarding the power to locate genes for complex disorders, that samples collected by individual investigators may not be sufficiently large to provide significant evidence for genetic linkage. Furthermore, once linkage has been demonstrated, even larger sample sizes are needed to identify and characterize susceptibility genes. Thus, it is clear that coordinated collaboration is needed to share findings and pool samples. Cooperative research of this type is often difficult. With the support of the Obsessive Compulsive Foundation, a group of investigators (described above) from around the world (the OCF Genetics Collaborative) have already begun to meet to address some of these issues. The OCF has funded the first two meetings of this group. However, its funds are [unreadable] limited and for the most part, donors to the OCF Research Fund indicate that they want the funds that they give to support specific research projects rather than meetings. Thus, the aim of this proposal is to obtain funding that will allow this group to continue meeting to establish collaborative working groups focused on different aspects of the genetics of OCD. The hope is that data from a variety of studies being done collaboratively among members of the group will be easily combined and stored in a general data repository to be used initially by all members of the OCF Genetics Collaborative and eventually by members of the scientific community at large. [unreadable] [unreadable]